1. Field of the Invention
The present invention relates to a method and an apparatus for metering a flow of a liquid or for determining the mass or weight thereof
2. Description of the Prior Art
U.S. Pat. No. 4,030,356 discloses a continuous weighing mechanism, wherein the liquid flow to be weighed is supplied to a liquid receiver comprising two liquid receiving trays mounted on a common rocker shaft. When one tray has been filled with liquid the shaft rotates, whereby the other tray is moved to a liquid filling position while said one tray is being emptied. The mass of the liquid having passed the liquid receiver is calculated on the basis of the number of the rocking movements registered by an electric circuit. The accuracy of measurement of this known apparatus is, however, less satisfactory when the liquid flow to be measured varies, because varying liquid flow causes that the rocking liquid receiving trays will be influenced by varying forces of inertia.
U.S. Pat. Nos. 2,853,877 and 3,937,083 and British patent specification No. 1,089,159 disclose liquid metering devices comprising a metering or measuring chamber having a float member arranged therein. The measuring chamber has an inlet and an outlet with inlet and outlet valves, respectively. The liquid to be measured is passed into the measuring chamber through the inlet while the outlet is closed by the outlet valve. When the liquid supplied to the measuring chamber has moved the float member to a predetermined upper level it causes the inlet valve to be closed and the outlet valve to be opened so that the liquid may flow out of the measuring chamber through its outlet under the influence of its own gravity. When the float member has been moved downwardly to a predetermined lower position the outlet valve is closed while the inlet valve is open, and the operation just described is thereafter repeated. Due to the fact that the liquid is discharged from the measuring chamber through the outlet valve exclusively under the influence of its own gravity the capacity of the known metering apparatuses described above is rather limited.